The present application relates to wearable wireless electronic devices, and in particular, to tag-like or patch-like wireless devices that can adhere to human skin.
Wearable tags can communicate with smart phones and other devices using WiFi, Bluetooth, or NFC technologies. Near Field Communication (NFC) is a wireless communication standard which enables two devices in a short range to establish a communication channel within a short period of time through radio waves in the 13.56 MHz frequency range. NFC can be a useful technology for data transfer between two devices in close proximity to one another. Because it needs the two devices to be in close proximity to one another (less than 10 cm), it is more secure than other wireless technologies like Bluetooth and Wi-Fi. Hence, it can be seen as an easy and secure tool for establishing quick two-way connections for data transfer. NFC is a two-way communication tool, one of the devices/cards can have a passive NFC tag that can reduce the cost and still behave in the same way as any other RFID tag.
This communication standard is being increasingly adopted for use in wireless transactions, including money transfer, loyalty coupons, gift cards, transit passes, tickets, etc. Mobile handset manufacturing companies are increasingly integrating NFC hardware in their phones. For example, the 2014 CES badges employed NFC technology and have resulted in shorter lines, more badge functionality, and greater ease of use for attendees and exhibitors. NFC has also been increasingly used in the fields of medical devices, electronic health records, as well as wearable tagging devices.
Wearable tag (or patch) is an electronic tag that can be worn by a user. Wearable tag is required to stay on user's skin and function for an extended period of time from hours to months. A wearable tag can contain a silicon chip and antenna that can be accessed using NFC, Bluethooth, WiFi, or other technologies. An authentication wearable tag can be used as a “password” similar to a barcode. For example, it can be used to recognize a user's smart phone for authentication purpose. It can also be integrated with different sensors for other purposes such as vital signs monitoring, motion track, skin temperature measurements and ECG detection.
Despite initial development efforts, conventional wearable tags still face several drawbacks: they may not provide adequate comfort for users to wear them; they may not stay attached to user's body for the required length of time; they are usually not aesthetically appealing.
Moreover, conventional wearable tags are often not robust enough to sustain repeated elongations during the movements of the body that the wearable tags are attached to. Under stress, different layers in wearable tags can break or delaminate rendering the tags inoperable.
Another challenge to conventional wearable tags is that their conductive circuits cannot provide high quality (high Q) wireless communications. One cause for this deficiency is due to the resistance in the antenna circuits in these conventional wearable tags.